The present invention relates in general to call redirection and, in particular, to a method and system for using a lightweight directory access protocol (LDAP) to redirect calls.
Conventionally, calls placed in the Public Switched Telephone Network (PSTN) require offboard lookups to redirect the call to the correct destination. For example, when a caller makes an 800 or 888 long-distance call, wherein a service access code (SAC) is translated into a directory number, or when a caller makes a local number portability (LNP) call, wherein a local routing number is used alongside the original directory number to route the call to its destination, a Signaling System 7 (SS7) Transaction Capabilities Application Part (TCAP) stack performs the necessary query from the switch to an offboard signaling transfer point (STP) and Signaling Control Point (SCP). Such SAC or LNP queries may also be performed using proprietary data protocols such as an X.25 network, or the like.
A drawback with using the SS7/TCAP stack, together with the STP and SCP, to perform SAC and/or LNP queries is that 30-40% more time is consumed routing redirected calls than is consumed routing non-redirected calls. This causes more blockage of telephone lines, and reduces the traffic capacity of telephone switches. SS7/TCAP stack systems are also relatively expensive. Accordingly, a continuing search has been directed to the development of methods and systems which can be used to perform SAC and/or LNP queries and to redirect calls more quickly and cost-effectively than is possible using a SS7/TCAP stack, SCP, and STP combination.
According to the present invention, SAC and/or LNP queries and the redirecting of calls is improved by using a TCP/IP stack and LDAP protocol in lieu of an SS7/TCAP stack, SCP, and STP. This permits the use of internet protocols which are less expensive and faster than an SS7/TCAP stack, SCP, and STP, thereby reducing telephone line blockage and increasing the traffic capacity of telephone switches.